• Mycobiology
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• v.48 no.6
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• pp.501-511
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• 2020

Xylophagous termites are capable of degrading lignocellulose by symbiotic gut microorganisms along with the host's indigenous enzymes. Therefore, the termite gut might be a potential niche to obtain natural yeasts with celluloytic, xylanolytic and ethanologenic traits required for bioethanol production from lignocellulosic biomass. In this study, we cultured 79 yeasts from three different termites viz. Coptotermes heimi, Odontotermes javanicus and Odontotermes obesus. After suitable screening methods, we identified 53 yeasts, which belonged to 10 genera and 16 different species of both ascomycetous and basidiomycetous yeasts. Most yeasts in the present study represent their first-ever isolation from the termite gut. Representative strains of identified yeasts were evaluated for their cellulolytic, xylanolytic, and ethanologenic abilities. None of the isolates showed cellulase activity; 22 showed xylanolytic activity, while six produced substantial quantities of ethanol. Among xylanolytic cultures, Pseudozyma hubeiensis STAG 1.7 and Hannaella pagnoccae STAG 1.14 produced 1.31 and 1.17 IU of xylanase. Among ethanologenic yeasts, the strains belonging to genera Candida and Kodamaea produced high amount of ethanol. Overall, highest ethanol level of 4.42 g/L was produced by Candida tropicalis TS32 using 1% glucose, which increased up to 22.92 g/L at 35 ℃, pH 4.5 with 5% glucose. Fermentation of rice straw hydrolysate gave 8.95 g/l of ethanol with a yield of 0.42 g/g using the strain TS32. Our study highlights the gut of wood-feeding termites as a potential source of diverse yeasts that would be useful in the production of xylanase and bioethanol.

• Mycobiology
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• v.41 no.3
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• pp.121-125
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• 2013

Arbuscular mycorrhizal fungi (AMF) have mutualistic relationships with more than 80% of terrestrial plant species. This symbiotic relationship is ancient and would have had important roles in establishment of plants on land. Despite their abundance and wide range of relationship with plant species, AMF have shown low species diversity. However, molecular studies have suggested that diversity of these fungi may be much higher, and genetic variation of AMF is very high within a species and even within a single spore. Despite low diversity and lack of host specificity, various functions have been associated with plant growth responses to arbuscular mycorrhizal fungal colonization. In addition, different community composition of AMF affects plants differently, and plays a potential role in ecosystem variability and productivity. AMF have high functional diversity because different combinations of host plants and AMF have different effects on the various aspects of symbiosis. Consequently, recent studies have focused on the different functions of AMF according to their genetic resource and their roles in ecosystem functioning. This review summarizes taxonomic, genetic, and functional diversities of AMF and their roles in natural ecosystems.

• Journal of Microbiology and Biotechnology
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• v.26 no.8
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• pp.1490-1503
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• 2016

Colorectal cancer (CRC) is the third most common cancer in the world. Although 5-fluorouracil (5-FU) is the representative chemotherapy drug for colorectal cancer, it has therapeutic limits due to its chemoresistant characteristics. Colorectal cancer cells can develop into cancer stem cells (CSCs) with self-renewal potential, thereby causing malignant tumors. The human gastrointestinal tract contains a complex gut microbiota that is essential for the host's homeostasis. Recently, many studies have reported correlations between gut flora and the onset, progression, and treatment of CRC. The present study confirms that the most representative symbiotic bacteria in humans, Lactobacillus plantarum (LP) supernatant (SN), selectively inhibit the characteristics of 5-FU-resistant colorectal cancer cells (HT-29 and HCT-116). LP SN inhibited the expression of the specific markers CD44, 133, 166, and ALDH1 of CSCs. The combination therapy of LP SN and 5-FU inhibited the survival of CRCs and led to cell death by inducing caspase-3 activity. The combination therapy of LP SN and 5-FU induced an anticancer mechanism by inactivating the Wnt/β-catenin signaling of chemoresistant CRC cells, and reducing the formation and size of colonospheres. In conclusion, our results show that LP SN can enhance the therapeutic effect of 5-FU for colon cancer, and reduce colorectal cancer stem-like cells by reversing the development of resistance to anticancer drugs. This implies that probiotic substances may be useful therapeutic alternatives as biotherapeutics for chemoresistant CRC.

• Mycobiology
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• v.49 no.3
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• pp.235-248
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• 2021

This study aimed to understand whether the geo-ecological segregation of native plant species affects the root-associated fungal community. Rhizoplane (RP) and rhizosphere (RS) fungal microbiota of Sedum takesimense native to three geographically segregated coastal regions (volcanic ocean islands) were analyzed using culture-independent methods: 568,507 quality sequences, 1399 operational taxonomic units, five phyla, and 181 genera were obtained. Across all regions, significant differences in the phyla distribution and ratio were confirmed. The Chao's richness value was greater for RS than for RP, and this variance coincided with the number of genera. In contrast, the dominance of specific genera in the RS (Simpson value) was lower than the RP at all sites. The taxonomic identity of most fungal species (95%) closely interacting with the common host plant was different. Meanwhile, a considerable number of RP only residing fungal genera were thought to have close interdependency on their host halophyte. Among these, Metarhizium was the sole genus common to all sites. These suggest that the relationship between potential symbiotic fungi and their host halophyte species evolved with a regional dependency, in the same halophyte species, and of the same natural habitat (volcanic islands); further, the fungal community differenced in distinct geographical regions. Importantly, geographical segregation should be accounted for in national culture collections, based on taxonomical uniqueness.

• The Plant Pathology Journal
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• v.38 no.5
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• pp.432-448
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• 2022

Planthopper infestation in rice causes direct and indirect damage through feeding and viral transmission. Host microbes and small RNAs (sRNAs) play essential roles in regulating biological processes, such as metabolism, development, immunity, and stress responses in eukaryotic organisms, including plants and insects. Recently, advanced metagenomic approaches have facilitated investigations on microbial diversity and its function in insects and plants, highlighting the significance of microbiota in sustaining host life and regulating their interactions with the environment. Recent research has also suggested significant roles for sRNA-regulated genes during rice-planthopper interactions. The response and behavior of the rice plant to planthopper feeding are determined by changes in the host transcriptome, which might be regulated by sRNAs. In addition, the roles of microbial symbionts and sRNAs in the host response to viral infection are complex and involve defense-related changes in the host transcriptomic profile. This review reviews the structure and potential functions of microbes and sRNAs in rice and the associated planthopper species. In addition, the involvement of the microbiota and sRNAs in the rice-planthopper-virus interactions during planthopper infestation and viral infection are discussed.

• Korean Journal of Medicinal Crop Science
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• v.22 no.4
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• pp.306-312
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• 2014

Endophytes are microorganisms that live in the internal tissues of plants without harming the host plants. In this symbiotic relationship, the host plants provide nutrients and shelter to the endophytes, in turn, endophytes can promote the growth of host plants and act as a biological control agents against plant pathogens. Plant-microbe interactions like this are noted for natural methods for sustainable agriculture and environmental conservation. However, in spite of the infinite potential, there are only a few reports on the endophytes present in ginseng. In this study, we isolated and identified the endophytes from Panax ginseng seeds and evaluated the biological activities (IAA production ability, nitrogen fixation ability, phosphate solubilization capacity, siderophore production ability, and antifungal activities) of the endophyte isolates. Eight different endophytes were identified by 16S rRNA sequencing. Most of the endophytes have antibiotic and plant growth promoting (PGP) activities. Particularly, PgSEB5-37E have the highest antibiotic activity, both PgSEB5-37B and PgSEB5-37H have high PGP traits such as an abilities to produce IAA, solubilize phosphate and fix nitrogen. These results indicated that the endophytes from P. ginseng seeds may have applicable value to many industries. In order to use the isolated endophytes, quantitative analysis and field tests are needed to be performed.

• ALGAE
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• v.30 no.3
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• pp.233-239
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• 2015

Microalgae research is gaining momentum because of their potential biotechnological applications, including the generation of biofuels. Genome sequencing analysis of two model microalgal species, polar free-living Coccomyxa sp. C-169 and symbiotic Chlorella sp. NC64A, revealed insights into the factors responsible for their lifestyle and unravelled biotechnologically valuable proteins. However, genome sequence analysis under-explored cytochrome P450 monooxygenases (P450s), heme-thiolate proteins ubiquitously present in species belonging to different biological kingdoms. In this study we performed genome data-mining, annotation and comparative analysis of P450s in these two model algal species. Sixty-nine P450s were found in two algal species. Coccomyxa sp. showed 40 P450s and Chlorella sp. showed 29 P450s in their genome. Sixty-eight P450s (>100 amino acid in length) were grouped into 32 P450 families and 46 P450 subfamilies. Among the P450 families, 27 P450 families were novel and not found in other biological kingdoms. The new P450 families are CYP745-CYP747, CYP845-CYP863, and CYP904-CYP908. Five P450 families, CYP51, CYP97, CYP710, CYP745, and CYP746, were commonly found between two algal species and 16 and 11 P450 families were unique to Coccomyxa sp. and Chlorella sp. Synteny analysis and gene-structure analysis revealed P450 duplications in both species. Functional analysis based on homolog P450s suggested that CYP51 and CYP710 family members are involved in membrane ergosterol biosynthesis. CYP55 and CYP97 family members are involved in nitric oxide reduction and biosynthesis of carotenoids. This is the first report on comparative analysis of P450s in the microalgal species Coccomyxa sp. C-169 and Chlorella sp. NC64A.

• Journal of Microbiology and Biotechnology
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• v.30 no.4
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• pp.505-514
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• 2020

The symbiotic nature of the relationship between algae and marine bacteria is well-studied among the complex microbial interactions. The mutual profit between algae and bacteria occurs via nutrient and vitamin exchange. It is necessary to analyze the genome sequence of a bacterium to predict its symbiotic relationships. In this study, the genome of a marine bacterium, Pseudoruegeria sp. M32A2M, isolated from the south-eastern isles (GeoJe-Do) of South Korea, was sequenced and analyzed. A draft genome (91 scaffolds) of 5.5 Mb with a DNA G+C content of 62.4% was obtained. In total, 5,101 features were identified from gene annotation, and 4,927 genes were assigned to functional proteins. We also identified transcription core proteins, RNA polymerase subunits, and sigma factors. In addition, full flagella-related gene clusters involving the flagellar body, motor, regulator, and other accessory compartments were detected even though the genus Pseudoruegeria is known to comprise non-motile bacteria. Examination of annotated KEGG pathways revealed that Pseudoruegeria sp. M32A2M has the metabolic pathways for all seven vitamin Bs, including thiamin (vitamin B1), biotin (vitamin B7), and cobalamin (vitamin B12), which are necessary for symbiosis with vitamin B auxotroph algae. We also identified gene clusters for seven secondary metabolites including ectoine, homoserine lactone, beta-lactone, terpene, lasso peptide, bacteriocin, and non-ribosomal proteins.

• Journal of Microbiology and Biotechnology
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• v.19 no.4
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• pp.397-402
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• 2009

Kombucha tea(KT) is sugared black tea fermented with a symbiotic culture of acetic acid bacteria and yeasts, which is said to be tea fungus. KT is claimed to have various beneficial effects on human health, but there is very little scientific evidence available in the literature. In the present study, KT along with black tea(BT) and black tea manufactured with tea fungus enzymes(enzyme-processed tea, ET) were evaluated for hepatoprotective and curative properties against $CCl_4$-induced toxicity, using male albino rats as an experimental model by analyzing aspartate transaminase, alanine transaminase, and alkaline phosphatase in plasma and malondialdehyde content in plasma and liver tissues. Histopathological analysis of liver tissue was also included. Results showed that BT, ET, and KT have the potential to revert the $CCl_4$-induced hepatotoxicity. Among the three types of teas tried, KT was found to be more efficient than BT and ET. Antioxidant molecules produced during the fermentation period could be the reason for the efficient hepatoprotective and curative properties of KT against $CCl_4$-induced hepatotoxicity.

• Journal of the Korean Society of Costume
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• v.67 no.3
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• pp.1-14
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• 2017

Cycling has become a popular leisure activity, and many cycling enthusiasts have used cycling clothes as a form of expression, which often comes in wide range of colors. The study shows the importance of color in cycling clothing to meet the emotional needs of consumers. Furthermore, this study aims to provide comparative analysis between color of domestic and overseas cycling clothing brands, and color preference of Korean consumers in order to provide data, which can be used in satisfying consumers' needs for personal expression and emotional demands. Thus, the study expects to identify consumers' satisfaction for cycling clothing. The consumers were categorized by the frequency of cycling and their interest in fashion, and the following categories were made:potential consumers, casual cyclists with low fashion involvement, casual cyclists with high fashion involvement and frequent cyclists with high fashion involvement. Consumers preferred dark colors for their cycling clothing including jacket, top and pants, while 'frequent cyclists with high fashion involvement' preferred more diverse colors and tones. In the cycling clothing market, white and black were major colors, while red, orange and blue were major colors of chromatic color. In terms of shade, dark shade dominated the market. Comparing between preferred color and preferred product color, black was preferred for both, but no other colors showed such tendency. This study is based on empirical analysis and verification of color, which is the emotional element appealing to specific and segmented sports-apparel market. The study revealed that the data could be applicable to the design of future products.